Simulating ion transfer across a liquid–liquid interface and electrocapillarity based on the electrochemical potential of all ions in the system.

• A model based on the electrochemical potential of all ions at the liquid–liquid interface. • Evaluation of the voltammograms affected by the IR drops. • Estimation of capacitive currents under the voltammetric condition. • Reproduction of electrocapillary curves that satisfy thermodynamic requirements. The liquid–liquid interface between two immiscible electrolyte solutions is an important subject in electrochemistry because ion-transfer reactions can be controlled externally. The electrochemical potentials of ions determine their behavior in a liquid–liquid two-phase system. The electrochemical potential is a continuous function of the system assuming a linear transition region at the interface. A simulation model that considers the electrochemical potential of all ions in the system was constructed for the liquid–liquid interface under electrochemical-measurement conditions. This model facilitates evaluating ion-transfer voltammograms affected by IR drops and separating charging currents from Faraday currents. Moreover, the model enables electrocapillary curves to be determined. [ABSTRACT FROM AUTHOR]